One such container closure, and one such closure lid for the container neck of a container closure, are known from German Utility Model DE-U 299 28 541. This reference also describes how such container closures and closure lids are inserted, in order to seal off the container in the closing position of the closure lid, or upon rotation of the closure lid in the opening direction before the closure lid is finally released or removed from the container neck, to achieve a pressure relief on the basis of the still existing overpressure in the container interior, so that liftoff of the closure lid from pressure, which risks a burn injury from hot coolant as it shoots out, can be avoided.
In this prior art, one phenomenon of conventional container closures or closure lids, known as the champagne cork effect, is also described. In it, if the closure lid comes loose from the container neck, at elevated internal pressures, despite the radially inward-oriented tension that intrinsically presses the sealing ring against the annular groove, the sealing ring can still remain in contact with the inner wall of the container neck, if the sealing ring comes out of the region of the sealing face into the region of the neck enlargement, in the unscrewing direction of the closure lid. In other words, in this phenomenon, the sealing ring is lifted radially outward from the bottom of the annular groove by the overpressure in the container interior, so that after further unscrewing of the closure lid, the aforementioned champagne cork effect occurs from a sudden pressure relief. The aforementioned prior art avoids this phenomenon by providing that the annular rib toward the lid has pressure relief conduits, which connect the annular groove with the pressure relief chamber, or are open toward the side of the annular rib remote from the groove, whenever the sealing ring has been lifted from the bottom of the annular groove. Although this does substantially prevent the aforementioned champagne cork effect, nevertheless, because the overpressure is only partly reduced, a residual pressure in the container remains, which especially upon very fast release or unscrewing of the closure lid can still cause the closure lid to jump off suddenly, even if only slightly.